The present invention relates generally to the field of devices used as thermal barriers to cover an opening in a ceiling such as a scuttle or access hole, and a process for insulating such opening. More particularly to the field of devices used to insulate a ceiling opening enclosing the drop-down style folding attic ladder. More particularly to a device for reducing or preventing temperature gain or loss through the attic opening when the stair is in the extended position, as well as when the stair is retracted into the stored position.
Attics or unheated spaces above ceilings are generally entered through an access hole cut and framed in a ceiling. These openings generally require the use of a step or extension ladder to be brought into the living space and placed at the opening for access. This inconvenience prompted the adaptation of a foldable ladder that disappeared into the ceiling, but could be pulled down for access into the attic. Thus, retractable, foldable or collapsible stair assemblies have been in use for many years to provide access to an overhead space.
The retracted stair assembly is typically enclosed in a wood frame installed between ceiling joists in a hallway to provide access to the overhead attic space, as illustrated in U.S. Pat. No. 2,572,281 (1949) to Pierce. When closed up into the ceiling, the opening is covered from below by a plywood or hardboard panel attached to a stair section. The plywood panel is mostly decorative, but may have an insulated strip around its perimeter to reduce hot or cold air transfer.
The advantage of this type of access system is that a separate permanent stairway to an attic is not necessary. However, a permanent stairway typically has a door that can be easily opened and closed with each trip up and down the attic stairs, thus preventing a large temperature gain or loss. Folding stairs, on the other hand, typically remain in the open or extended position, as shown in FIG. 1 of '281, during an entire project such as moving boxes into or out of the attic. Since attic spaces with restricted access are typically neither heated nor cooled, they can contain a large volume of very hot or very cold air. Thus when the stairs are in the open position, the heat or cold from the attic space invades the living area causing discomfort to the occupants and increased heating or cooling costs to return the living space to comfortable temperature. It is simply too inconvenient for most individuals to open and close the stair unit for every trip to and from the attic space.
Various articles have been devised to remediate temperature gain or loss through the opening when the stairs are closed. Even though the cover may have a perimeter gasket or be comprised of an insulating material, the panel is generally not thick enough, or well fitting enough, to significantly reduce or eliminate the temperature transfer problem. U.S. Pat. No. 4,567,074 (1986) to Litaker provided an insulated cover that fit over a trap door panel thereby reducing the temperature transfer through the trap door when it was in the closed position. A possible improvement is disclosed by Hunter in U.S. Pat. App. 2004/0172893 wherein a prefabricated sheet metal panel provided an exterior protective surface covering a Styrofoam slab in contact with the bottom plywood cover of the stair unit that is exposed at the ceiling. The unit was slid over the plywood cover and securely fastened. The unit seals the opening using perimeter weather stripping or gasketing. However, these units attach to the stair unit cover and project downward from the ceiling, unless extra work and expense is done to recess the stair unit up into the ceiling to make the additional add-on cover flush with the ceiling plane. A similar objection is raised to the ceiling covers illustrated in U.S. Pat. No. 6,014,841 (2000) to McCoy et al. and U.S. Pat. No. 6,601,352 (2003) to Obermeyer et al. In addition, when the stair unit is opened these covers are disengaged and provide no insulative barrier. If the person has several articles to store or retrieve, the stair must remain open for an extended period of time and a flood of hot or cold air from the attic space invades the living area. The only practical way to reduce the large volume air exchange is to install a cover above the folded stair in the attic space. But a simple batting of insulation pulled over the opening before the stair is folded is inadequate to many persons who demand a more reliable, accessible and effective barrier.
Thus, there exists a need for an attic mounted access cover to (1) install above an opening, scuttle hole or folded stair unit, (2) in an attic space without the need for a finished floor surrounding the opening, (3) that is inexpensive to purchase, (4) requires a minimum of expense and time to install, (5) is easy to open and close in a repetitive and reliable manner, (6) provides a means of positive repeatable alignment when closed, (7) is constructed of sturdy substantially rigid material not easily damaged, (8) that would take up no more attic floor space, open or closed, than the footprint of the framing for the opening, (9) that provides superior insulating capability from the heat and cold of the attic space, and (10) may be modified after purchase to conform to various opening dimensions as needed. Numerous attic mounted devices have been developed to address one or more of these requirements.
U.S. Pat. No. 4,151,894 (1979) to Edwards discloses an insulating box-shaped cover made of wood, fiberglass or plastic, that is deep enough to receive the folded stair unit and could be rolled away from the opening as the operator ascends or descends the stair. The unit is not made of insulating materials, but may be double walled to accommodate insulation therein. However, the unit requires a finished floor surrounding the framed opening to permit the unit to roll back and forth, and there is no means provided to positively align the lower edge over the opening when closed, enabling free lateral movements, particularly when the stair unit slams shut against the attic framing. The '894 design would most certainly move and expose the opening to the attic air thereby defeating its purpose entirely.
Similarly, U.S. Pat. No. 4,658,555 (1987) to Steiner provided a double-walled, insulation-filled hatchway cover utilizing foam or fiberglass to act as a seal against a rough board face. This type of free-moving cover, like '894 above, requires the user to push the entire unit out of the way onto attic insulation or flooring. The claims state that the ‘interlocking surface’ is just a rough board and the ‘interlocking seal’ is merely fiberglass bat insulation on the edges to ‘impede shifting’ of the cap. Again, there is no means to allow repetitive alignment when open or closed to maintain optimum sealing. In addition, the fiberglass bat acting as a seal will wear down from contact with the rough board, and since it supports the weight of the cap, will compress down flush with the edge of the cover greatly reducing its ability to provide positive sealing from the attic air infiltration.
U.S. Pat. No. 4,281,743 (1981) to Fuller discloses a knockdown, segmented, box-shaped attic opening cover comprised of lightweight insulating materials, such as polystyrene foam, so that it could be readily and easily moved to cover or uncover the opening. While the light weight and segmented parts have certain advantages, the insulating material has no protective covering and thus could be easily damaged. Such foam with joints is also prone to fatigue in the elevated heat of an attic. Further, the design does not provide a positive sealing configuration on its bottom edge or at the segmented joints, it just rests in place like '894 above, and would therefore be easily shifted during closure of the attic stair unit. In addition, when such a free-standing cover is pushed aside and the person is working in the attic, there is nothing rigid to cover the exposed opening, presenting a possible safety issue for a person to fall through the opening, or a heavy object such as a box to cause the flimsy foam to collapse and drop through to the stair and floor below.
An improvement by Helbig in U.S. Pat. No. 4,312,423 (1982) discloses the insulated box-shaped opening cover preconfigured as a rigid foam packing box for shipment of the stair unit. With careful shipping and unpacking, the shipping box is then used as a lightweight cover for the stair opening. However, without a protective outer layer, damage to the foam during shipping would be expected considering the weight of the stair unit, along with the other disadvantages cited against '743 above.
Waters et al., in U.S. Pat. No. 4,344,505 (1982), utilized insulative material of sufficient thickness to form a substantially rigid frame and cover, and achieve an R value of at least 19 in the materials. Although the design is relatively light weight and provides an increased R value over '743 or '423 due to the thick rigid foam insulation, the foam insulation does not have a rigid protective covering leaving it susceptible to damage or collapse, as also stated against the preceding patents. In addition '505 does not disclose a means to positively attach the frame in place. Thus, we are led to believe that opening the cover will not cause the frame to shift. Without being secured, this light weight cover would certainly move around every time it was touched. The specification recites the option of a track mounting system, but it is not claimed.
U.S. Pat. No. 4,550,534 (1985) to Mariano et al. continues the use of rigid foam, but discloses it as a one piece molded dome-shaped cover that rests over the retracted stair and opens on a floor mounted hinge assembly. Again, the use of unprotected foam is prone to the damage as recited above. In addition, this unit requires a finished floor around the stair unit framing since the foam dome has a footprint larger than the framing. It also requires mounting a leaf spring behind the unit from the floor to the dome to aid in raising the cover, which most certainly would be an inconvenience projecting away from the cover. Further, it is quite large to ship as one piece for installation.
U.S. Pat. No. 4,591,022 (1986) to Sciambi et al. further discloses rigid foam employed in a foldable attic opening cover. As the person climbs the stair the cover is folded rearward of the opening behind the person and secured, causing the person to turn around while still on the stair to push and secure the folded members. While this arrangement does save some space, the act of turning around on the stair may present a safety issue for less-agile persons. In addition, this unit requires a finished floor around the stair unit framing since the foam frame has a footprint larger than the floor opening.
In U.S. Pat. No. 4,928,441 (1990), Daley improves upon the design of '534 by encapsulating the rigid foam tub within a plastic shell. However, this unit, like those above, required a finished floor around the stair unit framing since the foam dome has a footprint larger than the framing. It also required mounting exposed hinges lateral to the cover on the flooring to aid in raising and lowering the cover. These hinges, with a built in stop or rest for the open cover, could present a tripping hazard due to their exposed location. Further, like '534 it is quite large to ship as one piece for installation.
A further refinement of the use of insulating material to comprise the opening cover like '534 and '441 is illustrated in U.S. Pat. No. 5,274,966 (1994) to Daley wherein the segmented cover has a lateral hinge assembly molded therein. Daley addresses the shipping size issue by halving the unit. However, this assembly is still bulky to produce and ship, and easily damaged as unprotected foam. The cover also requires finished attic flooring like '534, '022 and '441 above because of its large footprint and hinge design. An alternative solution to the shipping issue was provided in U.S. Pat. No. 4,832,153 (1989) to Daw et al., wherein the cover was again made out of a plurality of lightweight insulting pieces, but configured such that the parts could be partially nested for shipping or storage. While shipping size and light weight are advantages, the design has the disadvantage of having a weak construction due to multiple segments, whether or not it is reinforced with fiberglass, and finished flooring since it is made to rest outside the stair unit framing. A further refinement by Dickinson in U.S. Pat. No. 5,475,955 (1995) provided an insulated telescoping assembly made out of lightweight material such as cardboard or plastic. The unit is shipped with the parts nested together, and then expanded to the appropriate length at installation. The design has the disadvantage of weak construction since it is hollow and made out of cardboard or thin plastic. In addition, it requires finished flooring around the stair unit since it has a much larger perimeter when expanded.
Lightweight construction was further enhanced by the disclosure of Freeman in U.S. Pat. No. 5,271,198 (1993) wherein cardboard was folded to compose a cover with hollow chambers that may be filled with insulation during installation. As in '955 above, the hollow cardboard shell has the disadvantage of weak construction and poor insulative ability, and this cover also requires finished flooring around the stair unit since it has a much larger perimeter. U.S. Pat. No. 5,623,795 (1997) to Padgett disclosed the use of a single thickness of cardboard to form an inexpensive cover resting on weather stripping. While cost effective, it shares the disadvantage of weak construction and poor insulative qualities with '198. U.S. Pat. No. 5,628,151 (1997) to Monat provided a similar lightweight cover except that pockets were provided in the structure in which insulation was placed at the time of installation. To seal off the attic air, it was designed to fit over the box framing of the stair like the cap of '490. But this design shares the disadvantage being oversized and of weak construction as noted in '795, '198 and others.
Seagren, in U.S. Pat. No. 5,867,946 (1999) showed that the singular use of insulating materials for attic opening covers, without an exterior protective layer, left the cover easily vulnerable to damage, required molds to fabricate, and large boxes to store and ship the units to installation. Whereas '946 disclosed individually fabricated side and top elements, comprised principally of a protective layer bonded to an inner insulating layer. These composite parts were fabricated flat without the need for molds, and shipped unassembled to minimize cost. However, the cover required finished attic flooring like '534, '022 and '441 above because of its large footprint and hinge design.
U.S. Pat. No. 4,337,602, (1982) to King, disclosed a flexible enclosure placed above a ceiling opening closed by a zipper or other fastener. While this arrangement, when closed would substantially prevent air movement, the thin material does not provide significant insulating value, the sidewalls could be easily damaged by a person carrying objects up and down the stairs, and the construction provides no safety capability. Continuing with the theme of a flexible removable cover, U.S. Pat. No. 4,675,225 (1987) to Cutler et al., disclosed a thermal blanket that stretched to cover the opening in the attic before the stair was closed. Exactly how you are to fit the blanket in place on the attic framing from below while standing on the stair is not disclosed. While this arrangement may prevent air movement, the thin material does not provide significant insulating value, and the construction provides no safety capability. A variation on the '602 concept of a flexible cover is disclosed by Williams in U.S. Pat. No. Re. 36,975 (2000) wherein an attic hatchway cover of tent-like structure utilizes a zipper to open and close the cover. Again, while the cover is flexible it does not contain significant insulating properties and is prone to damage due to its material, and the construction provides no safety capability.
In U.S. Pat. No. 6,223,490 (2001) to Wessley, a tall sleeve with an insulated removable cap was first installed in the framed ceiling opening. A collapsible stair unit was then installed within the sleeve. Thus air movement down from the attic is restricted by the presence of the cap and the sleeve walls extending vertically into the attic space. However, the sleeve walls may impede access to the attic. The tight fitting locking cap will require additional time and effort to remove and replace when laying on the attic floor or on unprotected insulation. This unit could not be used in an existing stair installation since the stair unit wood framing is fastened to the ceiling joists before the ceiling is finished.
To reduce the time and effort to move the cover, Vesperman in U.S. Pat. No. 4,541,208 (1985) disclosed use of parallel tracks to allow horizontal movement of a box-like pre-molded insulated cover, or enable the cover to raise from one side utilizing a hinge-like configuration in one track. However, the installation required existing finished flooring, and exact placement of the tracks to maximize sealing and prevent binding. In addition, like '505 above, there will be permanent tracks in place in the attic to move around or trip over during attic work and occupy a significantly larger area than just the framed opening. U.S. Pat. No. 5,220,757 (1993) to Hulligan did not use floor tracks, but rather a retractable flexible plastic plate or cover disposed in opposite parallel grooves of vertical side pieces, easy to open and close, thus providing a more convenient access to the attic space. However, the construction of the opening cover unit is quite large in comparison to the other inventions and it projects substantially into the attic space. It would restrict movement of large or cumbersome objects through the opening. In addition, the plastic plate provides no real insulating capability, and slides reward occupying additional attic space.
As noted above, the prior attempts at attic stair covers address only one or two specific issues important to the inventor, but ignore the other requirements beneficial to the consumer. The results from the references above are attic opening covers of ‘extremes’, from thin vinyl and cardboard covers, to large premolded domes of insulation, to an oversized expansive tambour-like apparatus. Thus, the consumer has to chose among the various devices based upon expense, or ease of installation, or size, or weight, without a choice encompassing all of these objectives.